Display arrangement and method for fabrication of a display arrangement

ABSTRACT

A display arrangement comprises a display, a conductive shield arranged at the display, a ferrite layer and a conducting line of an antenna. The ferrite layer is arranged between the conducting line and the conductive shield.

BACKGROUND OF THE INVENTION

The present invention is related to a display arrangement and to amethod for fabrication of a display arrangement.

Normal operation of a display, such as a liquid crystal display,generates a large amount of noise in close proximity to the display dueto the signals used during operation. The noise may have a disruptiveimpact on other systems, such as a radio frequency identificationreceiver system. In order to allow correct operation of the radiofrequency identification system and, in particular, to guarantee acorrect reception of data transmitted to a reader, the coupling effectbetween the liquid crystal display and an RF antenna has to be reduced.

Document US 2009/0179806 A1 refers to the mounting of an antenna forelectronic devices. A display casing comprises a non-conductive resinregion having an antenna mounting space disposed therein and a displaymodule accommodated in the display casing.

Document US 2011/0156969 A1 describes a printed antenna that comprisesan ink-printed layer, a hard substrate such as a liquid crystal displaypanel and a radiation conductor layer. The ink-printed layer is coatedon a surface of the hard substrate to form a non-transparent area.

In document US 2013/0234899 A1 electronic device antenna structures aredescribed. A layer of ferrite reduces interference between the antennaand internal device components.

Document US 2013/0229362 A1 is related to a touch display panelstructure having an antenna pattern. A ferrite sheet is disposed betweenthe antenna pattern and the touch sensor unit.

SUMMARY OF THE INVENTION

In an embodiment, a display arrangement comprises a display, aconductive shield arranged at the display, a ferrite layer and aconducting line of an antenna. The ferrite layer is arranged between theconducting line and the conductive shield.

Advantageously, interference between the antenna and the display isreduced since the conductive shield reduces the influence of electricfields and the ferrite layer reduces the influence of magnetic fields.Thus, an influence of the signals in the display on the signals in theantenna and an influence of the signals in the antenna on the displaycan be minimized.

In an embodiment, the display has a first main surface and a second mainsurface that is opposite to the first main surface. The conductiveshield is at least located at the first main surface of the display. Theferrite layer and the conducting line are arranged at the first mainsurface of the display. A distance of the ferrite layer to the firstmain surface is smaller than a distance of the ferrite layer to thesecond main surface. Consequently, a distance of the conducting line tothe first main surface is smaller than a distance of the conducting lineto the second main surface.

In an embodiment, the conductive shield covers at least a part of thefirst main surface of the display. The conductive shield covers an areaof the first main surface of the display at which the conducting line isarranged. There may be openings of the conductive shield at the firstmain surface of the display. The conducting line is optionally closelycoiled as a circular, rectangular or triangular curve. The conductiveshield may cover a first area of the first main surface of the displayat which the conducting line is arranged.

In an alternative embodiment, the first main surface of the display iscompletely covered by the conductive shield.

In an embodiment, the display comprises a side surface. The conductiveshield additionally covers a part of the side surface of the display.There may be openings in the conductive shield at the side surface.

In an embodiment, the conductive shield comprises an electric conductivematerial. The conductive shield may comprise a material of a groupconsisting of copper, aluminum, nickel, indium tin oxide and aconducting polymer.

In an embodiment, the conductive shield is a non-meshed film, foil orsheet.

Alternatively, the conductive shield may be a meshed film, foil orsheet. The meshes of the conductive shield have an opening that is lessthan a half of a wavelength of an electrical signal in the display orthe antenna. Optionally, the opening is less than a tenth of thewavelength.

In an embodiment, the conductive shield is realized as a rigid material.

In an alternative embodiment, the conductive shield is fabricated fromflexible material.

In an embodiment, the conductive shield performs shielding for thedisplay. The conductive shield may perform shielding for the displayonly.

In an embodiment, the conductive shield does not perform shielding forthe whole display arrangement or for a whole device comprising thedisplay arrangement.

In an embodiment, the ferrite layer covers a part of the first mainsurface of the display. The ferrite layer covers the area of the firstmain surface of the display at which the conducting line is arranged.The ferrite layer and the conducting line are at a rim of the first mainsurface of the display.

In an embodiment, the ferrite layer comprises a ceramic material madeout of a metal oxide. The metal oxide may be, for example, an iron oxidesuch as hematite Fe₂O₃ or magnetite Fe₃O₄. The material may be a softferrite, such as a manganese-zinc ferrite or a nickel-zinc ferrite, or ahard ferrite, such as a strontium ferrite, a barium ferrite or a cobaltferrite.

Alternatively, the ferrite layer may be designed as ferrite polymercomposite comprising a distribution of ferrite particles in a polymermatrix.

The ferrite layer may be electrically conducting or electricallynon-conducting.

In an embodiment, the ferrite layer prevents that a magnetic fieldgenerated by the antenna goes into the conductive shield. The ferritelayer achieves that magnetic field lines generated by the antenna closein the ferrite layer. Without ferrite layer, the magnetic field of theantenna would enter the conductive shield and would cause currents inthe conductive shield which will reduce the efficiency of the antenna.

In an embodiment, the display comprises image pixels formed fromlight-emitting diodes or organic light-emitting diodes.

In an embodiment, the display is realized as a liquid crystal display.

In an embodiment, the display is insensitive to touch. The displayarrangement is free of a touch sensor.

In an embodiment, the display is implemented as a touch-sensitivedisplay. Thus, the display may comprise a touch screen. The touch screenmay comprise a capacitive, inductive or resistive touch sensor. Thetouch screen can also be called touch panel or touch switch.

In an embodiment, the conducting line is not arranged at the part of thedisplay that is touch-sensitive.

In an embodiment, the conductive shield, the ferrite layer and theconducting line of the antenna are at the same side of the display ontop of each other.

In an embodiment, the display, the conductive shield, the ferrite layerand the conducting line of the antenna form a sequence with this order.The display, the conductive shield, the ferrite layer and the conductingline of the antenna may be stacked with this order.

In an embodiment, the display arrangement comprises an isolating spacerlocated between the conductive shield and the ferrite layer. Theisolating spacer is arranged at the rim of the first main surface of thedisplay. Optionally, the isolating spacer is electricallynon-conducting.

In an embodiment, the conductive shield, the isolating spacer, theferrite layer and the conducting line of the antenna are at the sameside of the display on top of each other.

In an embodiment, the display, the conductive shield, the isolatingspacer, the ferrite layer and the conducting line of the antenna form asequence with this order. The display, the conductive shield, theisolating spacer, the ferrite layer and the conducting line of theantenna may be stacked with this order.

In an embodiment, the isolating spacer is realized as a rigid material.

In an alternative embodiment, the isolating spacer is realized as afoam. The foam is implemented as solid foam. The solid foam can be usedas lightweight cellular material. The foam may be anopen-cell-structured foam, also called a reticulated foam, or aclosed-cell foam. The open-cell-structured foam contains pores connectedto each other, forming an interconnected network that is relatively softand filled with the medium they are surrounded with. The closed-cellfoam does not have interconnected pores. The closed cells can be filledwith a specialized gas to provide a high electrical insulation. Theclosed-cell structure foams advantageously have higher dimensionalstability, lower moisture absorption and higher mechanical strengthcompared to open-cell-structured foams.

In an alternative embodiment, the isolating spacer is realized as agas-filled gap. The gap is filled with air or another gas. The isolatingspacer comprises a rigid structure configured to provide the gap betweenthe conductive shield and the ferrite layer.

In an embodiment, the antenna has the form of a coil. The coil isrealized as a loop. The conducting line forms the coil. The coil isarranged at the rim of the first main surface of the display.

In an embodiment, the antenna is designed for radio-frequencyidentification, abbreviated to RFID, and/or for near fieldcommunication, abbreviated to NFC.

In an embodiment, a frequency band of the antenna falls between 10 MHzto 20 MHz. Optionally, the frequency of signals received and emitted bythe antenna is at 13.56 MHz.

In an embodiment, a reader comprises the display arrangement.Furthermore, the reader comprises a semiconductor body having a readercircuit. The reader comprises conductors which connect the display andthe conducting line to the reader circuit. The conductors may beflexible. The conductors may be implemented as a flexible printedcircuit.

In an embodiment, a method for fabrication of a display arrangementcomprises providing a display with a conductive shield arranged at thedisplay, providing a ferrite layer and providing a conducting line of anantenna. The ferrite layer is fixed between the conducting line and theconductive shield.

The ferrite layer and the conductive shield advantageously realize amethodology to reduce electric and magnetic influences from the displayto the antenna and vice versa.

In an embodiment, the conductive shield is realized by attaching anelectrically conductive foil to the display at a rim of a first mainsurface of the display. An adhesive may achieve the attachment of theconductive shield to the display.

In an embodiment, the ferrite layer is attached on a carrier film. Thecarrier film is attached to the conductive shield by a further adhesive.Thus, an isolating spacer is provided between the ferrite layer and theconductive shield by the carrier film of the ferrite layer and thefurther adhesive.

In an embodiment the isolating spacer that is placed between the ferritelayer and the conductive shield is fabricated as a foam, a gas-filledgap or a rigid material.

In an embodiment, the conducting line of the antenna is arranged on asubstrate. The substrate having the conducting line is attached to theferrite layer in the display. The substrate is attached to the ferritelayer by an additional adhesive.

BRIEF DESCRIPTION OF THE DRAWINGS

The following description of figures of exemplary embodiments mayfurther illustrate and explain the invention. As far as components,layers and method steps correspond to one another in terms of theirfunction in different figures, the description thereof is not repeatedfor each of the following figures.

FIGS. 1A and 1B show an exemplary embodiment of a display arrangement.

FIGS. 2A and 2B show a further exemplary embodiment of the displayarrangement with a conductive shield.

FIG. 3 shows a further exemplary embodiment of the display arrangement.

FIG. 4 shows an exemplary embodiment of a reader comprising the displayarrangement.

FIGS. 5A and 5B show a further exemplary embodiment of the displayarrangement and simulation results.

DETAILED DESCRIPTION

FIG. 1A shows an exemplary embodiment of a display arrangement 10comprising a display 11 and a conducting line 12. The display 11 isrealized as a housed display. The display 11 already comprises anenclosure, for example a plastic enclosure. The display 11 may beimplemented as a liquid crystal display, abbreviated to LCD. The display11 is unshielded.

The conducting line 12 forms an antenna 13. The conducting line 12 canalso be called an antenna trace. The conducting line 12 realizes HF coilconductive traces. The antenna 13 is realized as HF antenna. The antenna13 is implemented as a planar antenna. The conducting line 12 comprisesat least one turn. In the example shown in FIG. 1A, the conducting line12 performs two turns. The antenna 13 is realized as a coil-shapedantenna. The antenna 13 is used for RFID. The conducting line 12 andthus the antenna 13 are arranged on a first main surface 14 of thedisplay 11. The unshielded LCD 11 has the HF antenna 13 on top of it.The conducting line 12 is located closely to a border of a first mainsurface 14 of the display 11. Additionally, the display 11 comprises asecond main surface 15 and a side surface 16. The display 11 has theform of a cuboid or rectangular box and thus consists of six rectangularfaces. Two of them are the first and the second main surface 14, 15. Theother four rectangular faces can be summarized as the side surface 16.

A first area 17 of the first main surface 14 of the display 11 is notused for displaying content. The first area 17 is at the border of thefirst main surface 14 of the display 11. The conducting line 12 isarranged at the first area 17 of the first main surface 14 of thedisplay 11. A second area 18 of the first main surface 14 of the display11 is used for displaying content. The first area 17 surrounds thesecond area 18. The conducting line 12 does not cover the second area18.

FIG. 1B shows a cross-section of the display arrangement 10 shown inFIG. 1A. The conducting line 12 forms an outer turn 20 and an inner turn21. The conducting line 12 is arranged at a distance D from the firstmain surface 14 of the display 11. The display arrangement 10 comprisesconductors 22 that connect the display 11 to a circuit, not shown. Dueto the small distance D between the conducting line 12 and the display11, radiated noise generated by the display 11 is coupled into theconducting line 12. The radiated noise is emitted by signals that areused for driving the display 11. The conductors 22 are realized asflexible conductors such as a flexible cable or a flexible circuitboard. Noise generated by the LCD 11 is capacitively coupled to the HFantenna 13.

Noise generated by the display 11, such as an LCD, can be reduced bymodifying a LCD synchronization and refresh procedure during an IDoperation. An LCD-embedded controller, not shown, can be modified inorder to reduce transmitted signals during RF operation. Alternatively,an LCD electronics could be modified to reduce noise.

In an alternative embodiment, not shown, a lateral distance between thedisplay 11 and the conducting line 12 can have a value of a rangebetween 5 mm and 2 cm in the plane of the first main surface 14 of thedisplay 11 to avoid the noise. Additionally, the conducting line 12 mayhave an orthogonal distance D of up to 5 mm to the first main surface 14of the display 11. Thus, a physical separation between the display 11and the antenna 13 is achieved. Physical separation uses additionalspace and consequently increases the housing size of the displayarrangement 10 which in turn involves additional costs. This can beavoided by the display arrangement 10 as shown in the following figures.

FIG. 2A shows an exemplary embodiment of the display arrangement 10 thatis a further development of the display arrangement shown in FIGS. 1Aand 1B. For clarity reasons, the conducting line 12 is not shown. Thedisplay arrangement 10 comprises a conductive shield 30. The conductiveshield 30 is located at the display 11. The conductive shield 30exclusively covers the first area 17 of the display 11. Thus, theconductive shield 30 exclusively covers those parts of the surfaces ofthe display 11 that are not used for displaying content. The conductiveshield 30 does not cover the second area 18 that is used for displayingcontent. The conducting line 12, not shown, will be arranged on top ofthe conductive shield 30 in the first area 17. In addition, theconductive shield 30 also covers at least partial areas of the sidesurface 16 of the display 11. Thus, the conductive shield 30 is placedaround the display 11. The conductive shield 30 has the form of a coilhaving one turn. Optionally, the turn is closed.

The conductive shield 30 can be realized as a thin metal layer having athickness of less than 200 μm, optionally below 50 μm. The conductiveshield 30 may comprise copper or aluminum. The conductive shield 30 maybe implemented as a rigid structure or as a foil, film or sheet. Thefoil, film or sheet of the conductive shield 30 may be flexible. Theconductive shield 30 can be realized as a meshed foil, film or sheet.

Alternatively, the conductive shield 30 may be realized as a non-meshedfoil, film or sheet. Alternatively, the conductive shield 30 isfabricated by a conductive shielding tape.

The display 11 is realized as a touch-sensitive display. The second area18 is designed as a touchable or touch-sensitive area of the display 11.The display 11 is visible in the second area 18 due to the opening ofthe conductive shield 30 at the first main surface 14 of the display 11.The conductive shield 30 is implemented as an electrically floatingshield.

Advantageously, the conductive shield 30 reduces the influence of a highfrequency electromagnetic field. The conductive shield 30 reduces theinfluence of electric fields in high and low frequencies. The conductiveshield 30 reduces the noise coupling between the display 11 and theantenna 13, since the conductive shield 30 is added around the display11.

In an alternative embodiment, not shown, a reference potential or groundis provided to the conductive shield 30. For example, the conductiveshield 30 is connected to a reference potential terminal of the display11.

In an alternative embodiment, not shown, the conductive shield 30comprises at least one opening for providing an electrical contact tothe display 11. The at least one opening may be located at the sidesurface 16.

FIG. 2B shows another view on the display arrangement 10 illustrated inFIG. 2A. Whereas FIG. 2A elucidates a top view on the displayarrangement 10, FIG. 2B shows a bottom view. The conductive shield 30also partially covers the second main surface 15 of the display 11. Theconductive shield 30 has an opening at the second main surface 15.

FIG. 3 shows an alternative exemplary embodiment of the displayarrangement 10 that is a further development of the above-shownembodiments. The conductive shield 30 covers the first main surface 14of the display 11. The first main surface 14 is completely covered bythe conductive shield 30. The conductive shield 30 is realized as atransparent layer. The conductive shield 30 is fabricated from aconductive material, for example, such as indium tin oxide, atransparent electrically conducting polymer or a thin transparent metalfilm. The conductive shield 30 may also cover the side surface 16 andparts of the second main surface 15 of the display 11.

Furthermore, the display arrangement 10 comprises a ferrite layer 40.The ferrite layer 40 is arranged between the conducting line 11 and theconductive shield 30. The ferrite layer 40 is only located at the firstarea 17. Thus, the ferrite layer 40 does not cover the second area 18.The ferrite layer 40 is arranged such that it permits display of contentby the display 11. The ferrite layer 40 is located in the same area asthe conducting line 12. The ferrite layer 40 has low losses and highmagnetic permeability. The ferrite layer 40 has a high relativepermeability in the range of 90 to 600, for example, at a frequency of13.56 MHz. The relative permeability of the ferrite layer 40 optionallyis in the range of 130 to 170.

The ferrite layer 40 is fabricated with a thickness of less than 500 μm,for example less than 300 μm. The ferrite layer 40 optionally has athickness between 140 μm and 280 μm. The ferrite layer 40 is fabricatedfrom a ferrite material, a carrier film and an adhesive. The ferritematerial may be a sintered ferrite ceramic. The carrier film is realizedas an organic film such as polyethylene terephthalate, abbreviated toPET. The ferrite material may be enclosed by a protective layer, forexample also made from PET. Thus, the carrier layer, the ferritematerial and the protective layer are formed as a stack. The attachmentof the carrier layer to the ferrite material is achieved by an adhesive.

In addition, the display arrangement 10 comprises an isolating spacer41. The isolating spacer 41 is arranged between the ferrite layer 40 andthe conductive shield 30. The isolating spacer 41 is realized as a foam.The foam is a solid foam. For example, the isolating spacer 41 isimplemented as acrylic foam. The isolating spacer 41 may be fabricatedfrom an acrylic foam tape. The acrylic foam is a closed-cell foam. Thethickness of the isolating spacer 41 is less than 1 mm, optionallybetween 50 μm and 500 μm. The isolating spacer 41 separates the ferritelayer 40 from the conductive shield 30 such that a direct contact of theferrite layer 40 to the conductive shield 30 is avoided. The isolatingspacer 41 achieves a decoupling insulation.

The display 11 is designed as LCD. The display 11 comprises a housing42. The housing 42 is realized as a plastic encapsulation. Thus, thedisplay 11 is realized as a housed device. The housing 42 prevents anelectric contact between the conductive shield 30 and the inner parts ofthe display 11.

The conducting line 12 is arranged on a carrier 43. The conducting line12 is fabricated from electrically conducting material such as a metal,for example copper, aluminum, silver and gold, an electricallyconducting thick film paste, or an electrically conducting polymer. Thecarrier 43 is flexible or rigid. The carrier 43 may be realized as aflexible circuit board or printed circuit board.

The isolating spacer 41 is placed on top of the conductive shield 30.Finally, the antenna 13 is placed on top of the ferrite layer 40.

The inductively coupled noise from the display 11 to the antenna 13 isreduced. The isolating spacer 41 implemented as a gap made of acrylicfoam between the antenna 13 and the conductive shield 30 minimizes theinductive coupling between the display 11 and the antenna 13. A highlevel of magnetic field strength can be achieved in the operation in therange of a payment HF system by decoupling the HF coil antenna 13 fromthe metal structure of the conductive shield 30 by means of theisolating spacer 41.

Advantageously, a methodology to decouple the display 11 realized as anLCD and the antenna 13 implemented as a HF RFID antenna placed on top ofthe display 11 is achieved. A noise generated by the display 11 issuppressed. The decoupling between the display 11 and the antenna 13ensures that the signal transmission via the antenna 13 is notdisturbed. Signals received or emitted by the antenna 13 advantageouslydo not influence the displayed content.

Alternatively, the conductive shield 30 is fabricated from anon-transparent material but obtains meshes so that it is transparent inthe second area 18.

Alternatively, the isolating spacer 41 is realized by a gas-filled gap,such as an air gap. The gas-filled gap has a thickness of less than 1mm, optionally less than 500 μm. The gap may be filled with air oranother gas. A rigid structure of the isolating spacer 41 or the displayarrangement 10 may prevent the gas-filled gap from closing.

Alternatively, the isolating spacer 41 is made of a rigid electricallyinsulating material. The material may be a thermoplastic, athermosetting polymer or an elastomer. For example, the material may beacrylic, polypropylene, polystyrene, polyethylene, polyvinyl chloride,polyamide or polyurethane.

In an alternative embodiment, not shown, the isolating spacer 41 isomitted or reduced. The ferrite layer 40 may obtain a high thickness,for example more than 300 μm. The isolating spacer 41 may only comprisean adhesive for fixing the ferrite layer 40 to the conductive shield 30,a carrier layer of the ferrite layer 40 or a thin isolating layer on theconductive shield 30 for electrical isolation of the conductive shield30. The thicker ferrite layer 40 decouples the HF coil antenna 13 fromthe metal structure of the conductive shield 30.

FIG. 4 shows an exemplary embodiment of a reader 58 comprising thedisplay arrangement 10 according to one of the above-shown embodiments.According to FIG. 4, the conductive shield 30 does not cover the secondarea 18. Thus, the second area 18, at which the content is displayed bythe display 11, is free from the conductive shield 30. The conductiveshield 30 is fabricated by a conductive shielding tape. The conductiveshield 30 also covers a part of the side surface 16 of the display 11.The isolating spacer 41, the ferrite layer 40 and the conducting line 11are arranged in a stack form. The stack comprising the isolating spacer41, the ferrite layer 40 and the conducting line 11 is attached to thefirst main surface 14 of the display 11.

The display 11 comprises a liquid crystal unit 50 and a backlight 51attached to the liquid crystal unit 50. The liquid crystal unit 50 islocated near the first main surface 14 and the backlight 51 is locatednear the second main surface 15 of the display 11. Moreover, the display11 comprises a touch screen 52 that is located at the first main surface14 of the display 11. Thus, the touch screen 52 is arranged at theliquid crystal unit 50. An optically clear adhesive fixes the touchscreen 52 to the liquid crystal unit 50. The display 11 is realized as astack of the touch screen 52, the liquid crystal unit 50 and thebacklight 51. For electrical connection, a printed circuit board 53 isattached to the backlight 51. The liquid crystal unit 50 and thebacklight 51 are electrically connected to the printed circuit board 53via pins 54 and contact bumps 55.

In addition, the reader 58 comprises a semiconductor body 59. Thesemiconductor body 59 is realized as a reader circuit. The semiconductorbody comprises a NFC transceiver circuitry. The semiconductor body 59 iselectrically coupled to the conducting line 12 via further conductors57. The semiconductor body 59 is foreseen for providing signals to andreceiving from the antenna 13. In addition, the semiconductor body 59 isalso electrically coupled to the backlight 51 and the liquid crystalunit 50 via the conductor 22. Furthermore, the touch screen 52 iselectrically coupled via additional conductors 56 to the semiconductorbody 59. The semiconductor body 59 is arranged on a flexible circuitboard 61. The flexible circuit board 61 is split into the conductors 22,56, 57. Thus, the flexible circuit board 61 connects the antenna 13, thetouch screen 52, the backlight 51 and the liquid crystal unit 50 to thesemiconductor body 59. The flexible circuit board 61 may be implementedas a rigid-flex circuit. The semiconductor body 59 may be implemented asa NFC initiator and/or HF reader integrated circuit.

In addition, a tag 62 is shown in FIG. 4 that is coupled to the reader58. The tag 62 is implemented as an RFID tag or smart card. A furtherantenna 63 of the tag 62 can provide information to the antenna 12 ofthe reader 58. The dimensions of the antenna 12 and of the display 11are chosen to fit with the dimensions of the tag 62. Thus, a furthersemiconductor body 64 of the tag 62 can communicate with thesemiconductor body 59 of the reader 58.

The reader 58 may be configured as smart card reader. The reader 58 isdesigned for applications such as EMV payment, access control, NFCinfrastructure and ticketing. EMV is the abbreviation of Europay,MasterCard and Visa, a global standard for inter-operation of integratedcircuit cards, abbreviated to IC cards or chip cards, and IC cardcapable point of sale terminals and automated teller machines, forauthenticating credit and debit card transactions. EMVco is theorganization responsible for developing and maintaining the EMVstandard.

Advantageously, a correct operation of the HF RFID system is achieved. Acorrect reception of data transmitted by the tag 62 to the reader 58 isrealized. The reader 58 is designed for a payment application.Advantageously, the reader 58 is realized as a very compact unit. Thetag 62 can be implemented as a HF tag, HF card or HF label. The tag 62may be implemented as a proximity integrated circuit card, abbreviatedto PICC. The decoupling of the antenna 13 and the display 11 canadvantageously be realized without any change in the firmware orhardware by adding the conductive shield 30 and the isolating spacer 41providing insulation between the conductive shield 30 and the HF antenna13. Thus, customers may advantageously adapt the HF RFID technology tothe LCD 11, especially in a payment application such as an EMVco system.The RFID system can be integrated in an already existing reader withonly small modifications. A change of the LCD operation or hardware canadvantageously be avoided. A coexistence between the noise generated bythe LCD 11 and a radio reception operation is achieved without any largechanges in the display hardware and operation.

The isolating spacer 41 and the ferrite layer 40 will boost theperformance of the antenna 13 which enables a payment operation, forexample according to EMVco requirements. In a payment application, theamount of power the reader 58 needs to deliver is close to 1 Watt.Advantageously, the efficiency of the HF coil antenna 13 is kept veryhigh by the display arrangement 10. This can be achieved by the use ofthe ferrite layer 40 and the isolating spacer 41 avoiding power lossesin the conductive shield 30. Advantageously, the reader 58 can read thetag 62 at a high distance, for example more than 7 cm. Thus, the EMVcorequirements in the term of power transfer and reception efficiency inthe EMVco-defined operating volume from 0 cm up to 4 cm, as defined inthe related standard, can be fulfilled.

The reader 58 avoids that noise generated from the display 11 iscapacitively coupled to the antenna 13. Consequently, noise is not fedinto a receiving path, abbreviated to Rx path, of the RFID reader 58 andinjected on the receiver causing a reception problem of signalstransmitted to the reader 58 from the tag 62.

FIG. 5A shows an exemplary embodiment of the display arrangement 10 thatis further development of the embodiments illustrated in FIGS. 3 and 4.The display arrangement 10 has a rectangular form.

FIG. 5B shows an exemplary simulation result obtained with the displayarrangement 10 shown in FIG. 5A. In the simulation result, a magneticfield strength H is shown versus a distance d. The magnetic fieldstrength H is illustrated in arbitrary units. The distance d=0 is at thecentral point of the display arrangement 10 shown in FIG. 5A. Simulationresults of the magnetic field strength H with and without a gap areshown: The upper curve shows the magnetic field strength H with anisolating spacer 41 realized as a gap whereas the lower curve shows themagnetic field strength H without an air gap spacer 41. The isolatingspacer 41 results in a higher value of the magnetic field strength H.The current flowing through the conducting line 12 has the same valuefor both cases. Thus, the same value of the current flowing through theantenna 13 results in a higher value of the magnetic field strength H,if the isolating spacer 41 decouples the ferrite layer 40 from theconductive shield 30. An isolating spacer 41 made of acrylic foam hassimilar properties in comparison to an air gap. Advantageously, theisolating spacer 41 and the ferrite layer 40 allow a decoupling betweenthe LCD 11 and the HF coil antenna 13 with a minimum amount of space.

The invention claimed is:
 1. A display arrangement, comprising adisplay, a conductive shield arranged at the display, a ferrite layer,and a conducting line of an antenna, wherein the conductive shieldcovers a first area of a first main surface of the display at which theconducting line is arranged and the ferrite layer is arranged betweenthe conducting line and the conductive shield.
 2. The displayarrangement according to claim 1, wherein the conductive shieldcompletely covers the first main surface of the display.
 3. The displayarrangement according to claim 1, wherein the display comprises a sidesurface and the conductive shield additionally covers a part of the sidesurface.
 4. The display arrangement according to claim 1, wherein theconductive shield comprises a material of a group comprising copper,aluminum, nickel, indium tin oxide and a conducting polymer.
 5. Thedisplay arrangement according to claim 1, wherein the conductive shieldis realized as a meshed film, sheet or foil.
 6. The display arrangementaccording to claim 1, wherein the display is implemented as a liquidcrystal display.
 7. The display arrangement according to claim 1,wherein the display is realized as a touch-sensitive display.
 8. Thedisplay arrangement according to claim 1, comprising an isolating spacerbetween the conductive shield and the ferrite layer.
 9. The displayarrangement according to claim 8, wherein the isolating space isrealized as rigid material.
 10. The display arrangement according toclaim 8, wherein the isolating spacer is realized as a gas-filled gap ora foam.
 11. The display arrangement according to claim 1, wherein theconducting line forms a coil of the antenna and is arranged at theborder of a first main surface of the display.
 12. The displayarrangement according to claim 1, wherein the antenna is designed forradio-frequency identification and/or near field communication.
 13. Areader, comprising: a display arrangement, comprising: a display; aconductive shield arranged at the display; a ferrite layer; and aconducting line of an antenna, wherein the conductive shield covers afirst area of a first main surface of the display at which theconducting line is arranged and the ferrite layer is arranged betweenthe conducting line and the conductive shield; a semiconductor bodycomprising a reader circuit, and conductors which couple the display andthe conducting line to the semiconductor body.
 14. A method forfabrication of a display arrangement, comprising providing a displaywith a conductive shield arranged at the display, providing a ferritelayer, and providing a conducting line of an antenna, wherein theconductive shield covers an area of a first main surface of the displayat which the conducting line is arranged and the ferrite layer is fixedbetween the conducting line and the conductive shield.